Adding histograms showing fraction of page load times

chrome/browser/net/cache_stats.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_NET_CACHE_STATS_H_
+#define CHROME_BROWSER_NET_CACHE_STATS_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/hash_tables.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
+#include "base/time.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "net/base/network_delegate.h"
+
+class TabContents;
+
+namespace base {
+class Histogram;
+}
+
+namespace net {
+class URLRequest;
+class URLRequestContext;
+}
+
+#if defined(COMPILER_GCC)
+
+namespace BASE_HASH_NAMESPACE {
+template <>
+struct hash<const net::URLRequestContext*> {
+  std::size_t operator()(const net::URLRequestContext* value) const {
+    return reinterpret_cast<std::size_t>(value);
+  }
+};
+}
+
+#endif
+
+namespace chrome_browser_net {
+
+// This class collects UMA stats about cache performance.  It is a singleton

[rvargas (doing something else), 2012/07/26 02:13:43]

nit: outdated comment.

[tburkard, 2012/07/26 02:50:54]

Done.

+// and lives on the IO thread.
+class CacheStats {

[rvargas (doing something else), 2012/07/26 02:13:43]

I'm afraid the class name (and file name) will be obsolete pretty soon... when
we start recording network numbers, this will not be cache specific.

I guess the renaming can be done later, but it may be simpler to do it now.

[tburkard, 2012/07/26 02:50:54]

yes
On 2012/07/26 02:13:43, rvargas wrote:

+ public:
+  enum TabEvent {
+    SPINNER_START,
+    SPINNER_STOP
+  };
+  void OnCacheWaitStateChange(const net::URLRequest& request,
+                              net::NetworkDelegate::CacheWaitState state);
+  void OnTabEvent(std::pair<int, int> render_view_id, TabEvent event);
+  void RegisterMainURLRequestContext(const net::URLRequestContext* context);
+  void UnregisterMainURLRequestContext(const net::URLRequestContext* context);
+  CacheStats();
+  virtual ~CacheStats();
+
+ private:
+  struct TabLoadStats;
+  typedef std::map<std::pair<int, int>, TabLoadStats*> TabLoadStatsMap;

[rvargas (doing something else), 2012/07/26 02:13:43]

This map deserves a comment.

[tburkard, 2012/07/26 02:50:54]

Done.

+
+  // Gets TabLoadStats for a given render view.
+  TabLoadStats* GetTabLoadStats(std::pair<int, int> render_view_id);
+  // Deletes TabLoadStats no longer needed for a render view.
+  void RemoveTabLoadStats(std::pair<int, int> render_view_id);
+  // Sets a timer for a given tab to collect stats.  timer_index indicates
+  // how many times stats have been collected since the navigation has started
+  // for this tab.
+  void ScheduleTimer(TabLoadStats* stats, int timer_index);
+  // The callback when a timer fires to collect stats again.
+  void TimerCb(TabLoadStats* stats, int timer_index);
+  // Helper function to put the current set of cache statistics into an UMA
+  // histogram.
+  void RecordCacheFractionHistogram(base::TimeDelta elapsed,
+                                    base::TimeDelta cache_time,
+                                    bool is_load_done);
+
+  TabLoadStatsMap tab_load_stats_;
+  std::vector<base::Histogram*> final_histograms_;
+  std::vector<base::Histogram*> intermediate_histograms_;
+  base::hash_set<const net::URLRequestContext*> main_request_contexts_;
+};
+
+// A WebContentsObserver watching all tabs, notifying CacheStats
+// whenever the spinner starts or stops for a given tab, and when a renderer
+// is no longer used.
+class CacheStatsTabHelper : public content::WebContentsObserver {
+ public:
+  explicit CacheStatsTabHelper(TabContents* tab);
+  virtual ~CacheStatsTabHelper();
+  virtual void DidStartProvisionalLoadForFrame(
+      int64 frame_id,
+      bool is_main_frame,
+      const GURL& validated_url,
+      bool is_error_page,
+      content::RenderViewHost* render_view_host) OVERRIDE;
+  virtual void DidStopLoading(content::RenderViewHost* render_view_host)
+      OVERRIDE;

[rvargas (doing something else), 2012/07/26 02:13:43]

nit: I believe this cannot be in a line by itself.

[tburkard, 2012/07/26 02:50:54]

Done.

+
+ private:
+  // Calls into CacheStats to notify that a reportable event has occurred
+  // for the tab being observed.
+  void NotifyCacheStats(CacheStats::TabEvent event,
+                        content::RenderViewHost* render_view_host);
+
+  CacheStats* cache_stats_;
+  bool is_profile_otr_;

[rvargas (doing something else), 2012/07/26 02:13:43]

nit: is_otr_profile_

[tburkard, 2012/07/26 02:50:54]

Done.

+};
+
+}  // namespace chrome_browser_net
+
+#endif  // CHROME_BROWSER_NET_CACHE_STATS_H_